The present invention relates to a tube with an integrated heating element for laparoscopy. By means of a humidifying material in the interior of the tube the gas introduced during laparoscopy is heated and humidified. The present patent application claims the priorities of the previous German applications DE 102013000492.6 (date of filing: 15 Jan. 2013) and DE 1020130100967.6 (date of filing: 18 Jun. 2013).
Laparoscopy is a medical intervention by means of which the abdominal cavity and the organs therein can be visually examined. For this purpose, small skin incisions (0.3-2 cm) in the abdominal wall are typically made, and a trocar is introduced therethrough, which in turn can accommodate an optical device. With the aid of a special endoscope (laparoscope), the abdomen can be examined. In diagnostic laparoscopy, the abdomen is only visually inspected, and in a therapeutic process, operative interventions can also be performed.
Typically, at the beginning of the laparoscopy, the abdomen is filled with gas, in order to create a pneumoperitoneum. For this purpose, various gases have already been used, such as air, nitrogen or carbon dioxide (CO2). The use of carbon dioxide gas has proven particularly successful. It was found that it is reasonable, in particular with longer laparoscopic interventions, on the one hand to heat the introduced gas and on the other hand to humidify it. The gas heating is intended so that the patient is not cooled down, and to avoid a diffuse feeling of pain in the patient, which probably is a consequence of a local cooling upon the entry of cold gas. The humidification serves for preventing drying out the inner abdominal surfaces, in order to avoid the cooling occurring thereby. It is important herein to achieve a relative gas humidity of more than 90% during the laparoscopy. When employing this in laparoscopy, the peculiarity results that the volume flows will strongly vary. An average gas flow of 1-3 l/min. can be assumed. If there should be, however, a larger leakage, for instance by activation of a ventilation, then immediately gas flow rates >20 l/min. are required, and these, too, should achieve the required humidity level of more than 90%.
For this purpose, the prior art provides suggestions. For instance, the German patent specification DE 19510710 describes a device that provides a means for adjusting the gas humidity (for instance a sponge) and which optionally may include an additional heating element.
U.S. Pat. No. 6,068,609 discloses an alternative device with a chamber that on the one hand comprises a sponge material, on the other hand provides a resistor heating. The humidification chamber includes a Luer lock port, which permits water to be filled into the chamber. The chamber of U.S. Pat. No. 6,068,609 is brought by corresponding ports into the gas flow of the insufflation device. Further prior art includes documents EP 0827417B1, US 2010/0206308 A1, DE 4331559 A1, and DE 4211986 A1.
The devices known from the prior art have technical drawbacks.
On the one hand, the chamber disposed at patient's side prevents the operability of the insufflation tube during the operative intervention. Due to the size and the weight of the chamber, it may be disturbing in the near operational field to the doctor in charge.
Further, the humidification rates of the gas for different flow rates cannot be kept at uniformly high levels. In particular, the short way of the gas through the chamber prevents an optimum humidification at high flow rates.
In order to increase the humidification capacity, the gas is conducted in the above solutions through a material (for instance a sponge). Thereby, the counter-pressure of the tube is substantially increased, and the maximum flow capacity is decreased. This has considerable disadvantages when maintaining the pneumoperitoneum. In particular, if high refill rates are required (for instance when using suction pumps), the insufflation capacity may under certain conditions not be sufficient, and the pressure in the abdominal cavity may possibly not be maintained.
Further, the introduction of the additional chamber for the humidification of the gas is disadvantageous for the production cost of the insufflation tube. The additionally required parts will substantially increase the cost.